Optimizing Target Responses

[Carl-NC]

It think this is the right place for this question.
Last week during casual conversation with my supplier I discovered that the MOSFET protection resistors he had sold me, generally 3R3, were in fact wire wound. Does this affect coil performance in anyway ? 3W metal film resistors are difficult to source - can I used metal oxide instead ?
Very educational thread; thanks guys.

I would guess that wire-wound is fine. I would measure the inductance to ensure it is "in the mud."

It is my recollection that metal oxide has high flicker noise. For the coil series R that doesn't matter but for the damping and clamping R's it does.

[Carl-NC]

The latex hypertext is not working in my browser. It produces broken image links.

I'm not sure what to do about that. Copy/paste the following line into your browser URL and see what you get:

https://www.geotech1.com/cgi-bin/mimetex.cgi?i=1

There should be a small image of "i=1".

[MartinB]

If my memory serves me right, I have asked similar questions about this. Dang, cant find em.

Yes, you can use MOX (metal oxide) resistors instead. I only use them now unless in a pinch.
Do check the voltage ratings though. There are quite a few el cheapo brands out there that are not really up to snuff on that.

I used to use the old fashioned dark green glazed wirewound ones. Some of them are bifilar? wound.
I assume you have the light grey/white rectangle box type ones.

Is there a difference? I did not have an oscilloscope back then, so cant definitely say.
You will surely get some sort of "extra effects" with inductive wirewound ones.
I would have to unpack my measuring gear to measure the magnitude of the difference.
Maybe its neglegible, but interesting nontheless.

Maybe Carl or someone else could elaborate on this.

Thanks Polymer
I will see what I can measure.
Carl has also responded.

[MartinB]

I would guess that wire-wound is fine. I would measure the inductance to ensure it is "in the mud."

It is my recollection that metal oxide has high flicker noise. For the coil series R that doesn't matter but for the damping and clamping R's it does.

Thanks Carl
I was also sold wire wound for the damping resistor, which I know does make a difference.
Looking for a suitably rated metal film resistor now.
Pleased that I had the conversation with my supplier before I boxed everything up.

[Qiaozhi]

The latex hypertext is not working in my browser. It produces broken image links.

Works fine for me in Firefox on Linux.
What browser and OS are you using?

Clearing the cache may solve the problem, or it may be a browser add-on that's causing problems.

[Teleno]

Works fine for me in Firefox on Linux.
What browser and OS are you using?

Clearing the cache may solve the problem, or it may be a browser add-on that's causing problems.

Chrome in both Android and Windows 10 show the broken image icon.

The same in MS browser in W10.

I looked at the HTML source and it seems the image URLs are nor url-encoded, that might be the cause.

If I copy the image address and paste it on the address bar then the images show, but still not on the web page even after reloading.

[6666]

Chrome in both Android and Windows 10 show the broken image icon.

The same in MS browser in W10.

I looked at the HTML source and it seems the image URLs are nor url-encoded, that might be the cause.

If I copy the image address and paste it on the address bar then the images show, but still not on the web page even after reloading.

Working ok in win7 with fire fox and chrome, will try win10 later.

[6666]

Something is not working right
Part 5 is broken, post #24

The graphics show ok but the Equations are broken in both win7/win10 both ff and chrome

[Qiaozhi]

Chrome in both Android and Windows 10 show the broken image icon.

The same in MS browser in W10.

I looked at the HTML source and it seems the image URLs are nor url-encoded, that might be the cause.

If I copy the image address and paste it on the address bar then the images show, but still not on the web page even after reloading.

Tried viewing the forum on a Windows 10 machine with Edge, Samsung Android phone with Chrome, and Samsung Android tablet with Chrome ... LaTeX images broken in all cases.

However, everything is ok on a Linux Mint laptop with Firefox.

Also just tested on Windows 10 with Firefox, and no broken LaTeX images.

Update: Tried Linux Mint with Chromium and FlashPeak Slimjet browsers ... LaTeX links broken.
So it appears that all browsers tested fail to display the LaTeX images, except Firefox.

[green]

Tried viewing the forum on a Windows 10 machine with Edge What I have. If I right click on image and open image in a new tab it seems to work for post #24. I'm computer stupid, so probably not understanding what is meant by broken. Just trying to learn something.

[6666]

Looks like its been fixed.

[Koala]

Tried viewing the forum on a Windows 10 machine with Edge What I have. If I right click on image and open image in a new tab it seems to work for post #24. I'm computer stupid, so probably not understanding what is meant by broken. Just trying to learn something.

correct

it doesn't display but will open in a new tab fine

[alex---1967]

Yes, better late than never!

Part 5:

The require damping resistor for critical damping is

[latex]
R_D = 0.5 \times \frac{L}{C_L} = 471\O

I think this is a mistake.


The result should be reduced by 1000 times.


This is how this formula should probably be written:





Rd = 0.001 * 0.5 * L / Cl






Example from calculations on the first page:






Rd = 0.001 * 0.5 * 300uH / 338pF = 0.001 * 0.5 * 0.0000300 / 0.000000000338 = 444 Ohm

[Carl-NC]

No, I was missing a square-root:



I've corrected post #24, good catch!

[detecto]

Hello everyone.
Car, question for you.
What software do you use to make graphs that you posted?
Thanks!